1. Field of the Invention
The present invention relates to a binder which removably binds from one to several pages, and more particularly relates to a paper binder which conducts retention by elastically pressing down upon the corner portion of the pages to be bound.
2. Description of the Related Art
When collecting and storing comparatively small-sized paper of memos, slips, or the like, wide use is made of a binder called a memo holder or memo binder where a freely pivoting pressing member is provided on one side of a hard mount, and where the free end side of the pressing member constantly is made to press against the mount by means of a spring. With regard to this type of binder, as a user successively receives or produces more memos or slips, the user opens the free end side of the pressing member against the spring force and places these memos or slips on top of the memos or slips already fastened on the mount, releases the force holding open the free end side of the pressing member, and thereby retains the paper by the pressing member. Thus, retention is made possible by an extremely simple operation. In the case where the bound memos or slips are removed from the binder, the user merely has to open the free end side of the pressing member, which is very convenient.
The concept for the pressing and binding of paper in such a manner as mentioned above is not only used for small-sized paper such as memos and slips, but is also used in binders which fasten comparatively large materials and report paper of B5 and A4 size, as well as large pages of copier paper, etc. That is, a pressing means is provided so that the left side area of the paper to be bound is pressed against the rear cover of a cover composed from a front cover, a rear cover, and a back cover. The pressing means is composed from a lever which is supported so that one end is freely movable, and a pressing member which is released when the free end of the lever is lifted, which forms a belt and is elastically pressed to the rear cover side when the free end of the lever is turned so as to make the lever horizontal, and which presses the left side area of the paper to be bound.
With regard to these types of holders or binders, not only it is extremely simple to bind and release paper as explained above, but also since it is also unnecessary to open a hole in the paper for purposes of having a pipe, a string, a band or the like pass through in order to bind the paper, no injury is inflicted on the paper.
The aforementioned holders or binders are preferable from the standpoint of inflicting no injury on the paper, but since one side of the paper is pressed down, it is difficult to leaf through the paper when numbers of pages are bound together. Moreover, in the case of memos or slips, the size varies according to the user and the dimensions of the recorded contents, and unevenness tends to occur. In this context, when the user conducts blanket binding without regard to size, and when the user later looks over these memos or slips, particularly in the case where the user looks at a small memo or slip which is fastened underneath a large memo or slip, the user is not able to see it unless the user leafs through the pages so that the memo or slip which is fastened on top is strongly bent over. Yet, if the bending force becomes stronger than the pressing force of the pressing member, it is no longer possible to press the memos or slips, and the memos or slips fall away from the pressing member.
Furthermore, in the case of comparatively large paper of B5 or A4 size, the elasticity of the paper also becomes larger compared to memos or slips, and a stronger pressing force is required of the pressing means. Yet, if a spring with a large spring elasticity is used in order to obtain a strong pressing force, it also becomes necessary to apply a strong force in turning the lever, and handling becomes difficult.
Additionally, in the case where a large number of pages are bound, the binding portion becomes larger as it goes to the rear, the inconvenience arises that the edge of the opened portion is covered by the binding portion and cannot be seen.